We have proposed a concrete and scalable architecture for quantum computing with light.
By using a hybrid resource state that can be generated and manipulated using near-future photonic technology, our architecture synthesizes modern techniques in scalable entangled resource state generation and bosonic codes.
This “best of both worlds” hybrid approach comes with a novel error structure that arises from the Gaussian model of state imperfections and the use of probabilistic bosonic qubit sources.
Numerical results show that such errors can be handled by our tailored two-tier decoder that makes use of continuous- and discrete-variable syndrome data.
We find that fault-tolerant quantum computation is possible in the regime where the swap-out probability – the likelihood that that any given bosonic qubit source failed and the input was swapped with a squeezed state – is smaller than \(\approx 23.6\%\) .
For an experimentally accessible squeezing value of \({15}{}\) , our numerical results suggest that the maximum tolerable swap-out probability is \(\approx 13.3\%\) .
This level of squeezing has been attained in free-space implementations [1]}, while the current state-of-the-art level of squeezing demonstrated in integrated sources is 8 dB [2]}; it remains an open experimental problem to match the level of squeezing in integrated sources to the free-space record.
In the remainder of this section, we discuss some technological aspects of the architecture.
